Latch mechanism for spray gun



Aug. 13, 1968 F. M. M DOUGALL LATCH MECHANISM FOR SPRAY GUN 2 Sheets-Sheet 1 INVENTOR FRANK UN M. MCDOUGAL Elll-Illll Filed March 28, 1966 FIG. 3

ATTORNEYS 3, 1968 F. M. MCDOUGALL 3,396,937

LATCH MECHANISM FOR SPRAY GUN Filed March 28, 1966 2 Sheets-Sheet 2 INVENTOR FRANKLIN M. McDOUGALL ATTORNEYS United States Patent 3,396,937 LATCH MECHANISM FOR SPRAY GUN Franklin M. McDougall, Kirkwood, Mo., assignor to Standard Machine & Manufacturing Company, St. Louis, Mo., acorporation of Missouri Filed Mar. 28, 1966, Ser. No. 537,944 9 Claims. (Cl. 251-107) This invention relates generally to improvements in a hand gun dispenser, and more particularly to an improved latch mechanism in a spray gun.

An important objective is to provide a latch mechanism that will lock the valve-actuating lever selectively in an infinite number of valve-opened positions between limits in order to obtain a desired flow rate and spray pattern.

Another important objective is achieved by the provision of a valve-actuating means carried by the body and operatively connected to a valve means, the valve-actuating means being manually movable between limits from a valve-closed position to valve-opened positions, and by the provision of a resilient pad carried by the body and engageable by a catch abutment on a latch means carried by the valve-actuating means.

Yet another important objective is afforded by the structural arrangement in which the valve-actuating means includes a lever pivoted to the body and extending adjacent to a hand grip and in which the latch means includes a latch arm pivotally connected to and carried by the lever, and by the provision of a resilient means tending to pivot the latch arm to urge the catch abutment against the resilient pad incident'to locking the lever in a valve-opened position. The latch arm is pivotally movable to disengage the catch abutment operatively from the pad to allow movement of the lever toward the valve-closed position.

An important objective is attained by the structural arrangement in which the catch abutment of the latch arm slidingly, yet frictionally, engages the resilient pad under the loading of the resilient means acting on the latch arm as the lever is moved pivotally away from the valveclosed position, and in which the catch abutment frictionally wedges in the resilient pad as the latch arm tends to pivot under the loading of the resilient means when the lever tends to move toward the valve-closed position, whereby to lock the lever in an adjusted valve-opened position.

Another important objective is realized by the provision of a second resilient means that is associated with the lever and tends to urge the lever toward the valve-closed position, the second resilient means exerting a force through the latch arm to wedge the catch abutment against the resilient pad when the lever is manually released.

Still another important objective is achieved by the provision of a pivot means that mounts the latch arm to the lever, the pivot means defining a pivot axis, and'by the provision of means that maintains the pivot axis at a lesser distance from the resilient pad than the distance from the pivot axis to the catch abutment as the lever moves between its limits, whereby to assure that the catch abutment will ride frictionally on the resilient pad as the lever is moved from the valve-closed position and to assure that the catch abutment will wedge in the resilient pad under loading of a resilient means in the desired valve-opened position upon release of the lever. It is advantageous for simplicity of construction, and for ease and dependability of operation to maintain the pivot axis on which the latch arm is mounted at a substantially constant distance from the resilient pad engaged by the catch abutment of the latch arm.

An important objective is afforded by the provision of. a

a part of the valve means mounted for reciprocative movement, which includes a pivot pin and means for moving the pin and plunger in a substantially straight path as the lever is swung between its limits, the resilient pad being disposed at a substantially constant distance from the pivot pin as the pin is moved upon actuation of the lever. The latch arm is pivotally mounted on the pin, and the resilient means tending to urge the catch abutment against the resilient pad, is operatively connected between the lever and latch arm.

Another important objective is attained by the structural arrangement in which the distance from the pivot pin to the catch abutment is greater than the distance from the pivot pin to the resilient pad, and by the provision of a second resilient means tending to urge the lever toward the valve-closed position. The catch abutment of the latch arm wedges in the resilient pad under the loading of both resilient means, i.e., the resilient means tending to pivot the latch arm and the second resilient means tending to urge the lever, upon manual release of the lever and latch arm.

A further important object is to provide a latch mechanism in a spray gun that is simple and durable in construction, economical to manufacture and assemble, highly eflicient in operation, and which can be operated by anyone with little or no instruction.

The foregoing and numerous other objects and advantages of the invention will more clearly appear from the following detailed description of a preferred embodiment, particularly when considered in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view of the spray gun with a part of the handle cut away to show the latch mechanism clearly and with the valve means shown incrosssection, the valve-actuating lever being disposed in the valve-closed position;

FIG. 2 is a side elevational view similar to FIG. 1, but showing the valve-actuating lever locked in an adjusted valve-opened position;

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is a fragmentary, enlarged side elevational view, partly in cross-section, showing the latch arm moved to a position in which the catch abutment is disengaged from the resilient pad.

FIG. 5 is a fragmentary, enlarged elevational view similar to FIG. 4, but showing the latch arm moved to a position in which the catch abutment is wedged in the resilient pad;

FIG. 6 is an exploded perspective view of the lever, and latch mechanism, and

FIG. 7 is a diagrammatic view illustrating the various forces acting on the latch arm in different positions of the lever.

Referring now by characters of reference to the drawlugs, and first to FIGS. 1 and 2, it will be understood that the spray gun includes a body generally indicated by 10 having a depending front flange 11 and a hand grip 12 of a pistol grip type. Located rearwardly of the front flange 11 and located on the underside of the body 10 is a substantially center recess 13. Defining the rear side of the recess 13 is a stop 14 formed integrally with the body 10. The purpose and function of the stop 14 will be described later.

vAttached to and carried by the body 10 is a valve means generally indicated by 15. The valve means 15 includes an elongate body 16 attached at one end to the body flange 11 by a pair of screws 17, one of which is shown in FIG. 2. The valve body 16 is provided with an internal chamber 20 and a discharge outlet 21 interconnected by a valve port 22 defined by a valve seat 23. The

valve body 16 is provided with an inlet 24 communicata ing with the chamber 20.

Reciprocatively mountedin the Valve body 16 and in the front body flange 11 is a plunger 25. The plunger 25 extends into the chamber 20 and is adapted to interfit the valve port 22 as is best seen inFIG. 1. An elongate stem 26 is aflixed to and carried by the inner end of plunger 25, the stem 26 having a flared head 27. The stem 26 extends into and through the valve port 22, the flared head 27 cooperates with the walls of the valve body defining the discharge outlet 21 and valve port 22 to define different spray patterns depending upon the adjusted position of the stem 26 and head 27 within the valve port 22.

A valve disc 30 is fixed to and movable with the plunger 25. The valve disc 30 is movable toward or away from the valve seat 23 upon reciprocative movement of plunger 25. In the valve-closed position of the plunger 25, the

valve disc 30 engages the valve seat 23 and closes the valve port 22 as shown in FIG. 1.

The outer end of plunger extends into and across the recess 13 behind the front body flange 11. The outer end of plunger 25 is engageable with the stop 14 to determine the maximum valve-opened position of the plunger 25.

Located within the chamber 20 0f the valve body .16 is a compression spring 32, constituting a resilient means. The spring 32 is located aboutthe plunger 25. One end of the spring 32 engages a disc 33 and a sealing washer contiguous to the valve body 16 at one endof the chamber 20, while the other end of spring 32 engages the valve disc 30. The spring 32 tends to urge the valve disc toward the valve seat 23, and hence tends to urge the plunger 25 toward its valve-closed position shown in FIG. 1.

The valve-actuating means includes an elongate lever 34 constructed of a pair of side flanges 35 interconnected by an integral transverse web 36. The transverse web 36 is terminated short of the upper end of the lever 34 to provide a front opening 37. The upper ends of the side flanges 35 of lever 34 are pivotally connected to the body 10 by a pivot pin 40, the side flanges 35 embracing opposite sides of the body 10. The lever 34 extends downwardly to a position adjacent the hand grip 12. The side flanges 35 of lever 34 enclose the opposite sides of the body recess 13.

The outer end of plunger 25 extends between and 4 latch arm 43 is provided with a front slot through which the plunger 25 extends. In the unlatched position of the latch arm 43 or the valve-closed position of lever 34, the latch arm 43 substantially covers the front opening 37 of the lever 34. The upper margin of the latch arm 43 constitutes a catch abutment 46, the purpose and function of which will appear upon later description of parts.

is pivotally connected to the side flanges 35 of lever 34 by a transverse pivot pin 41 defining a pivot axis. Specifically, the pivot pin 41 is carried by. the outer end of plunger 25 and is received in small slots 42 formed in the side flanges 35 of lever 34. Because the plunger 25 is constrained to reciprocative movement in a rectilinear or straight path, the pivot pin 41 carried by the plunger any infinite number of adjusted valve-opened positions,

such as that illustrated in FIG. 2, until the outer end of plunger 25 abuts the stop 14.

The operator, using this spray gun, holds the grip 12 and squeezes the lever 34 to move the valve disc 30 away from the. valve seat 23 and to move the stem head 27 into the valve port 22 until the desired flow rate and spray pattern is attained. At this point, the lever 34 is manually released and the lever 34 is locked automatically in the adjusted valve-opened position.

The latch means includes a latch arm generally referred to by 43. The latch arm 43 has a pair of laterally spaced flanges 44 pivotally mounted to the pivot pin 41 on opposite sides of the outer end of plunger 25. The

The resilient pad 47 is disposed adjacent to the. catch abutment 46 of the latch arm 43, and is disposed prefer ably at a constant distance from the path of travel of pivot pin 41. As will latter appear, the catch abutment 46 of the latch arm 43 is urged against the resilient pad 47. It will be importantly noted that the distance from the pivot pin 41 to the catch abutment 46 is greater than the distance from the pivot pin 41 to the resilient pad 47. It is this structural relationshipthat enables the lever to move freely from the valve-closed position to an adjusted valve-opened position as the catch abutment 46 slidingly and trictionally engages the resilient pad, and which enables the catch abutment 46 to wedge in the resilient pad 47 upon manual release of the lever 34.

A spring 50, constituting a resilient means, is operatively connected between the lever 34 and the latch arm 43. The structure of the spring 50 is perhaps best shown inFIG. 6. For example, the spring 50 is of substantially an inverted V-shape. A substantially U-shaped arm 51 of this spring 50 bears against the underside of the latch arm 43. The opposite arms 52 of the spring 50 seat against instruck tabs 53 formed integrally on the side flanges 35 of lever 34. The spring 50 has its coils 54, integrally interconnecting the opposed arms 51 and 52, located about the pivot pin 41.

The spring 50 tends to pivot the latch arm 43 about the pivot pin 41, and hence tends to urge the catch abutment 46 against the resilient pad 47. When the latch arm 43 is released, and the lever 34 is pulled rearwardly, the spring 50 tends to urge the catch abutment 46 against the resilient pad 47 and maintain a frictional contact. When the desired, adjusted valve-opened position is attained, the lever 34 is released, and the catch abutment 46 is wedged in the resilient pad 47 under the loading of spring 50 and e the spring 32. When the latch arm 43 is wedged, the lever 34 is locked in the desired valve-opened position until selectively released. I

The diagram of FIG. 7 illustrates the forces acting on and between the lever 34, latch arm 43 and resilient pad 47 to aiford the previously described locking function. For example, the arrow A represents the direction in which the latch arm 43 tends to rotate about pivot pin 41 under the loading of the spring 50, thereby causing the catch abutment 46 to be urged with a predetermined force against the underside of resilient pad 47. As the lever 34 is swung rearwardly about its pivot pin 40 from the valveclosed position illustrated in full lines to the adjusted valve-opened position illustrated in broken lines, it will be understood that the catch abutment 46 slides frictionally along the resilient pad 47 under the loading of spring 50. The pivot pin 41 moves in a straight path at a constant distance from the resilient pad 47 as is illustrated. When the lever 34 is released in this adjusted valve-opened position, the loading of the spring 32 acting through the plunger 25 and on pivot pin 41 tends to wedge the catch abutment 46 into the resilient pad 47 The horizontal component of force exerted on the pivot pin 41 is represented by the vector B. The wedging action locks the lever 34 in the desired valve-opened position.

It is thought that the functional advantages and operation have become fully apparent from the foregoing detailed description of parts, but for completeness of disclosure, the usage of this spray gun will be briefly described.

It will be assumed that initially the lever 34 is in its valve-closed position and that all of the associated component parts are in their corresponding positions, as is illustrated in FIG. I.

When it is desired to utilize the spray gun'to dispense a spray, the operator holds the hand grip 12 and squeezes the lever 34 to pivot the lever 34 rearwardly about its pivot pin 40, and consequently pulls theplunger 25 rearwardly'to open the valve port 22. The desired adjusted valve-opened'position of the lever 34 is attained when the operator is satisfied with the rate of flow through the valve port 22 and with the spray pattern formed by the position of the stem head 27 in the valve port 22.

"As the lever 34 is moved from the valve-closed position, it is moved against the loading of the compression spring 32. In addition, the catch abutment 46 of the latch arm 43 is urged under the loading of the spring 50 against the resilient pad 47, the catch abutment 46 sliding frictionally without binding along the'under'side of the pad 47.

When the desired adjusted valve-opened position of the lever 34 is achieved, the operator manually releases the lever 34. Immediately, the loading of the compression spring 32, acting through the pivot pin 41 and on the latch arm 43, tends to Wedge the catch abutment 46, already held frictionally against the resilient pad 47 under the loading of spring 50, in the resilient pad 47 to preclude movement of the lever 34 back toward the valve-closed position. It will be understood that there is no limit to the number of valve-opened positions of the lever 34 within its limits of movement. In .fact, the catch abutment 46 of the latch arm 43 can wedge in the resilient pad 47 at any point in its travel along the pad 47, thereby providing an infinite number of valve-opened positions within such limits.

If it is desired to move the lever 34 from one adjusted valve-opened position, which provides a given flow rate and spray pattem,to another adjusted valve-opened position, giving a greater flow rate and dilferent spray pattern, the operator merely squeezes the lever 34 again to swing the lever 34 rearwardly an even greater distance until the readjusted valve-opened position is achieved. During this movement of the lever .34, the latch arm 43 will automatically unlock, because. the pivot pin 41 travels rearwardly and the loading of compression spring 32 is removed from the latch arm 43 so that the catch abutment 46 moves out of wedging engagement with the resilient pad 47 and slidably engages the pad 47 under the loading of spring 50. Upon subsequent manual release of the lever 34, the latch arm 43 will again move into wedging engagement with the resilient pad 47 to lock the lever 34 in the readjusted valve-opened position, in the same manner as previously described.

To release the lever 34 and to enable movement of the lever 34 back to the valve-closed position or to a readjusted valve-opened position in which the flow rate is reduced, the operator squeezes the latch arm 43 to pivot the latch arm 43 about the pivot pin 41 to remove the catch abutment from the resilient pad 47. This unwedging action is clearly illustrated by a comparison of FIGS. 4 and 5. While holding the latch arm 43 depressed against the loading of spring 50, the lever 34 will move forward under the loading of the compression spring 32. Of course, such forward movement of the lever 34 can be stopped by the operator at any time in a readjusted valve-opened position by manually releasing the latch arm 43 so that the catch abutment 46 will wedge again into the resilient pad 47.

It will be apparent from the foregoing description that the lever 34 can be swung rearwardly from the valveclosed position to any valve-opened position by squeezing the lever 34 only, and that the lever 34 will be automatically locked in such adjusted valve-opened position by manual release of the lever 34. To move the lever 34 in a direction toward the valve-closed position, the latch arm 43 must be depressed against the loading of spring 50 to unwedge the catch abutment 46 from the resilient pad 47, and the lever 34 must be held under manual control as the lever 34 moves forwardly to the readjusted position. The latch arm 43 must be manually released in order to obtain a locking of the lever 34 in the readjusted position.

Although the invention has been described by making detailed reference to a single preferred embodiment, such detail is to be understood in an instructive, rather than in any restrictive sense, many variants being possible within the scope of the claims hereunto appended.

I claim as my invention:

1. In a hand gun dispenser:

(b) a valve means carried by the body,

(c) a valve-actuating means carried by the body and operatively connected to the valve means, the valveactuating means being manually movable between limits from a valve-closed position to valve-opened positions,

(d) a latch means carried by the valve-actuating means and including a catch abutment, and

(e) a resilient pad carried by the body and engageable by the catch abutment to lock the valve-actuating means selectively in a valve-opened position.

2. A hand gun dispenser as defined in claim 1, in

which:

(f) the body includes a hand grip,

(g) the valve-actuating means includes a lever pivoted to the body and extending adjacent to the grip, the lever being operatively connected to the valve means and movable between limits from a valve-closed position to valve-opened positions,

(h) the latch means includes a latch arm pivotally connected to and carried by the lever, the latch arm having a catch abutment,

(i) the resilient pad is disposed adjacent the catch abutment,

(j) a resilient means is carried by the lever and tends to pivot the latch arm to urge the catch abutment against the resilient pad to lock the lever in a valveopened position, and

(k) the latch arm is pivotally movable to disengage the catch abutment operatively from the resilient pad to allow movement of the lever toward the valveclosed position.

3. A hand gun dispenser as defined in claim 2, in

which:

(1) the catch abutment slidingly, yet frictionally, engages the resilient pad under the loading of the resilient means acting on the latch arm as the lever is moved pivotally away from the valve-closed position, and

(m) the catch abutment frictionally wedges in the resilient pad as the latch arm tends to pivot under the loading of the resilient means when the lever tends to move toward the valve-closed position, whereby to lock the lever in an adjusted valveopened position.

4. A hand gun dispenser as defined in claim 3, in

which:

(n) a second resilient means is associated with the lever and tends to urge the lever toward the valveclosed position, the second resilient means exerting a force through the latch arm to wedge the catch abutment against the resilient pad when the lever is manually released.

5. A hand gun dispenser as defined in claim 2, in

which:

(1) a pivot means mounts the latch arm to the lever,

the pivot means defining a pivot axis,

(m) means maintains the pivot aXis at a lesser distance from the resilient pad than the distance from the pivot axis to the catch abutment as the lever moves between its limits,

(n) the catch abutment slidingly, yet frictionally, en-

gages the resilient pad under the loading of the resilient means acting on the latch arm as the lever is moved pivotally away from the valve-closed position, and

(o) the catch abutment frictionally wedges in the resilient pad as the latch arm tends to pivot under the loading of the resilient means when the lever tends to move toward the valve-closed position, whereby to lock the lever in an adjusted valve-opened position.

6. A hand gun dispenser as defined in claim 5, in

which:

(p) the last said means maintains the pivot axis at a substantially constant distance from the resilient pad that is engaged by the catch abutment of the latch arm mounted at the pivot axis.

7. A hand gun dispenser as defined in claim 2, in

which:

(1) a pivot means mounts the latch arm to the lever,

the pivot means defining a pivot axis,

(111) means maintains the pivot axis at a lesser distance from the resilient pad than the distance from the pivot axis to the catch abutment as the lever moves between its limits,

(n) the catch abutment slidingly, yet frictionally, engages the resilient pad under the loading of the resilient means acting on the latch arm as the lever is moved pivotally away from the valve-closed position,

() a second resilient means tends to urge the lever toward the valve-closed position,

(p) the catch abutment frictionally wedges in the resilient pad to lock the lever in an adjusted valveopened position as the latch arm tends to pivot under the loading of the first said resilient means and under the loading of the second resilient means exerted through the latch arm when the lever is manually released, and

(q) the latch arm is selectively pivoted against the loading of the first said resilient means to move the catch abutment away from the resilient pad and thereby release the lever. 8. A hand gun dispenser as defined in claim 2, in

which:

(1) the valve means includes a plunger mounted for reciprocative movement,

(m) a connection interconnects the lever and plunger including a pivot pin and means for moving the pin and plunger in a substantially straight path as the lever is swung between its limits,

(n) the latch arm is pivotally mounted on the pin,

(0) the resilient means is operatively connected between the lever and latch arm and tends to urge the catch abutment against the resilient pad, and

(p) the resilient pad is disposed at a substantially constant distance from the pivot pin as the pin is moved upon actuation of the lever.

9. A hand gun dispenser as defined in claim 8, in

which:

(q) the distance from the pivot pin to the catch abutment is greater than the distance from the pivot pin to the resilient pad,

(r) a second resilient means tends to urge the lever toward the valve-closed position, and

(s) the catch abutment wedges in the resilient pad under the loading of both resilient means upon manual release of the lever and latch arm.

References Cited UNITED STATES PATENTS 127,883 6/1872 Hotz .L l107 415,312 11/1889 Schneider 251-l07 X 2,525,615 10/1950 Peck 251-109 X 2,690,321 9/1954 Luna et al. 251116 2,899,169 8/ 1959 Klingler 251-107 2,937,813 5/1960 Rinkewich 251116 X 2,956,752 10/1960 Wahlin 251-114 X 3,330,527 7/ 1967 Nurkiewicz 251-114 M. CARY NELSON, Primary Examiner.

R. C. MILLER, Assistant'Examiner. 

1. IN A HAND GUN DISPENSER; (A) A BODY (B) A VALVE MEANS CARRIED BY THE BODY, (C) A VALVE-ACTUATING MEANS CARRIED BY THE BODY AND OPERATIVELY CONNECTED TO THE VALVE MEANS, THE VALVEACTUATING MEANS BEING MANUALLY MOVABLE BETWEEN LIMITS FROM A VALVE-CLOSED POSITION TO VALVE-OPENED POSITIONS, (D) A LATCH MEANS CARRIED BY THE VALVE-ACTUATING MEANS AND INCLUDING A CATCH ABUTMENT, AND (E) A RESILIENT PAD CARRIED BY THE BODY ENGAGEABLE BY THE CATCH ABUTMENT TO LOCK THE VALVE-ACTUATING MEANS SELECTIVELY IN A VALVE-OPENED POSITION. 